Kevin Liu Kevin Liu - 3 months ago 22
Android Question

Is there any way to enable scrollbars for RecyclerView in code?

As we saw, RecyclerView is more effective than ListView, so I prefer to use it in my project. But recently I have a trouble when put it in my custom ViewGroup. RecyclerView is easy to set scrollbars in xml like this:

<android.support.v7.widget.RecyclerView
android:id="@+id/recycler_view"
android:scrollbars="vertical"
android:layout_width="match_parent"
android:layout_height="match_parent" />


But I really can't find any method to set the scrollbars in code for RecyclerView, what I have tried is:

mRecyclerView.setVerticalScrollBarEnabled(true);


and then I saw this in Android's document.

So I tried to make my own LayoutManager and override the functions which I thought I need. But finally I failed. So can anyone tell me how should I make my own LayoutManager or just show me an other solution. Thank you!

Answer

At the moment it seems to be impossible to enable scroll bars programmatically. The reason for that behaviour is that Android does not call neither View.initializeScrollbarsInternal(TypedArray a) nor View.initializeScrollbars(TypedArray a). Both methods are only called if you instantiate your RecyclerView with an AttributeSet.
As a workaround I would suggest, that you create a new layout file with your RecyclerView only: vertical_recycler_view.xml

<android.support.v7.widget.RecyclerView
xmlns:android="http://schemas.android.com/apk/res/android"
android:scrollbars="vertical"
android:layout_width="match_parent"
android:layout_height="match_parent" />

Now you can inflate and add the RecyclerView with scrollbars everywhere you want: MyCustomViewGroup.java

public class MyCustomViewGroup extends FrameLayout
{
    public MyCustomViewGroup(Context context)
    {
        super(context);

        RecyclerView verticalRecyclerView = (RecyclerView) LayoutInflater.from(context).inflate(R.layout.vertical_recycler_view, null);
        verticalRecyclerView.setLayoutManager(new LinearLayoutManager(context, LinearLayoutManager.VERTICAL, false));
        addView(verticalRecyclerView);
    }
}